package com.example.reggie.controller;

import com.example.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

/**
 * 图片文件上传和下载
 */
@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {

    @Value("${reggie.path}")
    private String basePath;
    /**
     * 上传文件
     * @param file
     * @return
     */
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file) throws IOException {
        //file是一个临时文件，需要转存到指定目录
        log.info(file.toString());

        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));

        //使用UUID重新生成文件名，防止文件被覆盖
        String fileName = UUID.randomUUID().toString() + suffix;

        //创建一个目录对象
        File dir = new File(basePath);
        //判断文件是否存在
        if (!dir.exists()) {
            dir.mkdirs();
        }

        //将临时文件转存到指定位置
        file.transferTo(new File(basePath + fileName));

        return R.success(fileName);
    }

    /**
     * 文件下载
     * @param name
     * @param response
     * @throws FileNotFoundException
     */
    @GetMapping("/download")
    public void downLoad(String name, HttpServletResponse response) throws IOException {
        //输入流，通过输入流读取文件数据
        FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));

        //输出流，通过输出流将文件写回浏览器，在浏览器显示图片
        ServletOutputStream outputStream = response.getOutputStream();
        //设置响应格式
        response.setContentType("image/jpeg");

        int len = 0;
        byte[] bytes = new byte[1024];
        while ((len = fileInputStream.read(bytes)) != -1) {
            outputStream.write(bytes, 0 ,len);
            outputStream.flush();
        }

        //关闭资源
        fileInputStream.close();
        outputStream.close();
    }
}
